The World Health Organization is urging developing countries in Asia to restrict access to pesticides that are commonly used in suicide attempts.

Worldwide, an estimated three million cases of pesticide poisoning occur every year, resulting in more than 250,000 deaths, the health agency said. About 900,000 people die by suicide each year around the world.

It is estimated that in the last 10 years, between 60 per cent and 90 per cent of suicides in China, Malaysia, Sri Lanka, and Trinidad were due to pesticide ingestion.

Since studies suggest that most people who take their own lives act on impulse, some suicides could be prevented if access to the lethal pesticides was restricted, said Jose Bertolote, WHO co-ordinator of mental and brain disorders.

"We have very good studies interviewing people between the act of ingesting pesticides and their deaths. More than 95 per cent are desperate when they learn they are going to die," Bertolote told Reuters on the sidelines of a suicide prevention forum in Hong Kong on Thursday.

"They did not want to die, and that's the tragedy."

People who take pesticides tend to live in rural areas and may die before family members can get them to hospital. Many did not intend to die but were looking for attention, Bertolote said.

WHO said it has received reports of increasing numbers of suicides from pesticide in other Asian countries, as well as in Central and South America.

Better pesticide management needed

The agency recommends controlling access to pesticides. Continuing pilot studies suggest the strategy works better when part of a community education program that includes pesticide management.

In places where pesticide poisoning is common, health-care workers also need to be trained and equipped to manage the cases, WHO said in September to mark World Suicide Prevention Day.

Organophosphate-based pesticides are the main problem, Bertolote said. The chemicals are banned by international conventions, but countries such as China continue to make, export and use the products.

In parts of Asia, pesticide cans may be stored next to bottles of condiments, he said.

To prevent pesticide poisonings, Bertolote recommended that governments make some organophosphate pesticides illegal to produce while giving better instructions on how to use pesticides and reduce the amount kept stored.